Dual direction locking mechanism for telescoping steering column

ABSTRACT

A locking mechanism for a telescoping steering column includes an energy absorption strap having a plurality of teeth disposed therealong. Also included is a clamp bolt rotatably driven by an adjustment lever. Further included is an actuator body coupled to the clamp bolt and rotated therewith. Yet further included is a first lock cam coupled to the actuator body and engageable with the teeth of the energy absorption strap to lock the telescoping steering column in a first direction. Also included is a second lock cam coupled to the actuator body and engageable with the teeth of the energy absorption strap to lock the telescoping steering column in a second direction different than the first direction.

CROSS REFERENCE TO RELATED APPLICATIONS

This patent application is a divisional application of U.S. patentapplication Ser. No. 16/669,293, filed Oct. 30, 2019, which is adivisional application of U.S. patent application Ser. No. 15/711,217,filed Sep. 21, 2017, which claims the benefit of priority to U.S.Provisional Patent Application Ser. No. 62/397,637, filed Sep. 21, 2016,the disclosures of which are incorporated by reference herein in theirentireties.

BACKGROUND

The invention relates to vehicle steering columns and, moreparticularly, to a dual direction locking mechanism for telescopingsteering columns.

Steering column assemblies often include multiple portions that aretelescopingly adjustable relative to each other. This is desirable forindividual driver comfort and preference. Additionally, the telescopingrelationship facilitates a collapsible steering column that may providesafety advantages during an energy absorption event.

A locking mechanism is required to maintain the moveable portion of thesteering column at the desired position after telescoping adjustment.Some column assemblies provide what may be referred to as “infinitepositioning” with a single direction locking capability. Mechanisms thatlock in the forward direction, for example, typically are limited tousing clamp friction to resist steering column movement in the rearwarddirection. Assemblies that do not allow infinite positioning in atelescoping direction often require the driver to readjust the steeringcolumn and repeat the clamp lever locking cycle to eliminate a tooth ontooth engagement condition.

SUMMARY OF THE DISCLOSURE

In one aspect of the invention, a locking mechanism for a telescopingsteering column includes an energy absorption strap having a pluralityof teeth disposed therealong. Also included is a clamp bolt rotatablydriven by an adjustment lever. Further included is an actuator bodycoupled to the clamp bolt and rotated therewith. Yet further included isa first lock cam coupled to the actuator body and engageable with theteeth of the energy absorption strap to lock the telescoping steeringcolumn in a first direction. Also included is a second lock cam coupledto the actuator body and engageable with the teeth of the energyabsorption strap to lock the telescoping steering column in a seconddirection different than the first direction.

In another aspect of the invention, a locking mechanism for atelescoping steering column includes an energy absorption strap having aplurality of teeth disposed therealong. Also included is a first lockcam engageable with the teeth of the energy absorption strap to lock thetelescoping steering column in a first direction. Further included is asecond lock cam engageable with the teeth of the energy absorption strapto lock the telescoping steering column in a second direction. Yetfurther included is a spring biasing the lock cams into engagement withthe teeth of the energy absorption strap into a locked condition. Alsoincluded is an adjustment lever having a cam profile engageable with atleast one of the lock cams upon rotation of the adjustment lever toovercome the spring bias of the lock cams to disengage the lock camsfrom the energy absorption strap into an unlocked condition.

In yet another aspect of the invention, a steering column assemblyincludes a lower jacket and an upper jacket in telescoping engagementwith the lower jacket. Also included is an energy absorption strapoperatively coupled to the lower jacket and the upper jacket, the energyabsorption strap having a plurality of teeth disposed therealong.Further included is a first lock cam engageable with the teeth of theenergy absorption strap to lock the upper jacket in a first direction.Yet further included is a second lock cam engageable with teethassociated with the upper jacket to lock the upper jacket in a seconddirection opposite to the first direction. Also included is a clamplever that is rotatable by an operator, rotation of the clamp levermoving the first lock cam and the second lock cam from a lockedcondition to an unlocked condition, the locked condition beingengagement between at least one tooth of the first lock cam with theteeth of the energy absorption strap and at least one tooth of thesecond lock cam with the teeth associated with the upper jacket, theunlocked condition being disengagement between the first and second lockcams with the respective teeth.

These and other advantages and features will become more apparent fromthe following description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter which is regarded as the invention is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other features, and advantages ofthe invention are apparent from the following detailed description takenin conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view of a steering column assembly with alocking mechanism in a locked condition according to an aspect of theinvention;

FIG. 2 is a perspective view of the steering column assembly of FIG. 1with the locking mechanism in an unlocked condition;

FIG. 3 is a perspective view of the locking mechanism of FIG. 1;

FIG. 4 is an elevational view of the locking mechanism of FIG. 1 in thelocked condition;

FIG. 5 is an elevational view of the locking mechanism of FIG. 1 in theunlocked condition;

FIG. 6 is a perspective view of a locking mechanism in a lockedcondition according to another aspect of the invention;

FIG. 7 is an elevational view of the locking mechanism of FIG. 6 in thelocked condition;

FIG. 8 is a perspective view of the locking mechanism of FIG. 6 in anunlocked condition; and

FIG. 9 is an elevational view of the locking mechanism of FIG. 6 in theunlocked condition.

DETAILED DESCRIPTION

Referring now to the Figures, where the invention will be described withreference to specific embodiments, without limiting same, a telescopelocking mechanism for a steering column is provided to allow “infinitepositioning” while also positively locking the steering column in aforward and rearward direction, as will be appreciated from thedisclosure herein.

Referring now to FIGS. 1 and 2, a portion of a steering column isillustrated and generally referenced with numeral 10. The steeringcolumn 10 includes several components, including an upper jacket 12 anda lower jacket 14 that are telescopingly engaged with each other in anaxial direction (i.e., longitudinal direction of steering column). Afirst side 16 of the portion of the steering column 10 is closer to thedriver, where a steering wheel would be positioned. A second side 18 ofthe portion of the steering column 10 is closer to a steering gear.

The steering column 10 may be used in any type of vehicle that requiressteering operation, including autonomous or semi-autonomous vehiclesequipped with an advanced driver assist system. A mounting bracket 20 isoperatively coupled to the steering column to allow adjustment orrelative motion of components of the steering column 10. Adjustment isfacilitated by manipulation of an adjustment lever 22 (may also bereferred to herein as a clamp lever) that is operatively coupled to thelower jacket 14. In particular, the adjustment lever 22 is coupled to aclamp bolt 26 that extends in a transverse direction through aperturesof the lower jacket 12 and through bracket apertures of the mountingbracket 20. Spaced outwardly of the mounting bracket 20 are one or morecomponents on each side of the mounting bracket 20. For example, aspacer 30 may be disposed on each side of the mounting bracket 20.

Actuation of the adjustment lever 22 allows a user to switch thesteering column between a locked condition (FIG. 1) and an unlockedcondition (FIG. 2). In the unlocked condition, a user is able totelescopiningly adjust the upper jacket 12 relative to the lower jacket14 to suit the user's preference. In the locked condition, relativemovement of components of the steering column 10 is inhibited. Asdisclosed herein, the adjustment lever 22 works in conjunction with alocking mechanism 40 that locks telescope travel in both the forward andrearward directions (or axially opposite directions) relative to anenergy absorption strap 42 that is operatively coupled to the upper andlower jackets 12, 14. The energy absorption strap 42 absorbs energyduring a collapse event of the steering column 10. In the illustratedembodiment, the energy absorption strap 42 is positioned on a bottomportion of the steering column 10, in what may be referred to as a 6o'clock position. It is to be appreciated that the energy absorptionstrap 42 may be positioned on an upper portion of the steering column10, in what may be referred to as a 12 o'clock position.

Referring now to FIGS. 3-5, the locking mechanism 40 is illustrated ingreater detail. The locking mechanism 40 includes an actuator body 44that is coupled to the clamp bolt 26 in a manner that facilitatessimultaneous and corresponding rotation by the actuator body 44 and theclamp bolt 26. The clamp bolt 26 is driven in a rotatable manner by theadjustment lever 22. Operatively coupled to the actuator body 44 are twolock cams. Specifically, a first lock cam 46 locks the telescopingmotion of the steering column 10 from moving in a forward direction anda second lock cam 48 locks the telescoping motion of the steering column10 from moving in a rearward direction. Each lock cam 46, 48 includes aplurality of teeth 50. At least one of each plurality of teeth isengageable with teeth 52 located along a surface of the energyabsorption strap 42 in a locked condition (FIG. 4) and disengaged toestablish the unlocked condition (FIG. 5).

The lock cams 46, 48 are spring loaded into engagement with the teeth 52of the energy absorption strap 42 (i.e., locked condition). To overcomethe spring bias, the actuator body 44 is rotated upon rotation of theclamp bolt 26 by the adjustment lever 22. Rotation of the actuator body44 directly, or indirectly through a lift linkage 54, overcomes thespring load and rotates the lock cams 46, 48 to the unlocked condition.In some embodiments, both lock cams 46, 48 are rotated to the unlockedcondition directly by the actuator body 44. In other embodiments, thelift linkage 54 rotates both cam locks 46, 48. In the illustratedembodiment, the lift linkage 54 disengages the second lock cam 48 andthe actuator body 44 directly disengages the first lock cam 46.

Referring now to FIGS. 6-9, another embodiment of the locking mechanismis illustrated and is referenced generally with numeral 140. In theillustrated embodiment, the energy absorption strap 42 is positioned ona side portion of the steering column 10, in what may be referred to asa 3 o'clock position or a 9 o'clock position. A mounting structure 144is mounted to the steering column 10 with a spring member 145 mountedthereto.

Operatively coupled to the spring member 145 are two lock cams.Specifically, a first lock cam 146 locks the telescoping motion of thesteering column 10 from moving in a forward direction and a second lockcam 148 locks the telescoping motion of the steering column 10 frommoving in a rearward direction. Each lock cam 146, 148 includes aplurality of teeth 150. At least one of each plurality of teeth 150 isengageable with the teeth 52 of the energy absorption strap 42 in alocked condition (FIGS. 6 and 7) and disengaged to establish theunlocked condition (FIGS. 8 and 9).

The lock cams 146, 148 are spring loaded into engagement with the teeth52 of the energy absorption strap 42 (i.e., locked condition) with thespring member 145. To overcome the spring bias, the adjustment lever 22is rotated to engage at least one of the lock cams 146, 148. Inparticular, the adjustment lever 22 includes a cam profile 122 along aportion that engages at least one of the lock cams 146, 148 to bias thelock cams 146, 148 out of engagement with the energy absorption strap42. In some embodiments, the cam profile 122 only engages one of thelock cams, where rotation of one lock cam results in rotation of theother lock cam. In other embodiments, the cam profile 122 engages bothlock cams.

As the lock cams 146, 148 are disengaged from the energy absorptionstrap 42, the locking mechanism 140, and therefore the telescopingsteering column 10, is transitioned to the unlocked position foradjustment thereof.

In some embodiments, the second lock cam, 48 or 148, is configured tolock directly to at least one of a plurality of teeth that are formed aspart of the upper jacket 12. As an alternative to direct toothengagement with the upper jacket 12, the second lock cam, 48 or 148, isconfigured to lock indirectly to the upper jacket 12 via one or moreintermediate components that is/are rigidly affixed to the upper jacket12. In such embodiments, engaging the second lock cam 48, 148 to theupper jacket 12 provides highly rigid rearward retention and/or allows amuch lower energy absorption strap load for forward direction collapse.For this option, the teeth that are on the energy absorption strap 42would be narrower, relative to the embodiments described above, and onlyreside under the first lock cam, 46 or 146.

Rather than relying on rearward motion resistance with clamp frictionprovided by tension created in the clamp bolt when the clamp lever isrotated to a locked position, the second cam lock 48, 148 disclosedherein enhances the rearward retention beyond the capacity generated bythe clamp pressure generated by the clamp bolt. It also may bebeneficial to create rearward retention load while allowing lower clampbolt tension which directly reduces the force required by the driver tolock the clamp lever. The enhanced retention is established by the dualdirection locking provided by the cam locks, while allowing infinitepositioning by a driver.

While the invention has been described in detail in connection with onlya limited number of embodiments, it should be readily understood thatthe invention is not limited to such disclosed embodiments. Rather, theinvention can be modified to incorporate any number of variations,alterations, substitutions or equivalent arrangements not heretoforedescribed, but which are commensurate with the spirit and scope of theinvention. Additionally, while various embodiments of the invention havebeen described, it is to be understood that aspects of the invention mayinclude only some of the described embodiments. Accordingly, theinvention is not to be seen as limited by the foregoing description.

What is claimed is:
 1. A locking mechanism for a telescoping steeringcolumn comprising: an energy absorption strap having a plurality ofteeth disposed therealong; a clamp bolt rotatably driven by anadjustment lever; an actuator body coupled to the clamp bolt and rotatedtherewith; a first lock cam coupled to the actuator body and engageablewith the teeth of the energy absorption strap to lock the telescopingsteering column in a first direction; and a second lock cam coupled tothe actuator body and engageable with the teeth of the energy absorptionstrap to lock the telescoping steering column in a second directiondifferent than the first direction, wherein the energy absorption strapis located on a top side of the telescoping steering column.
 2. Thelocking mechanism of claim 1, wherein the first lock cam and the secondlock cam are biased into engagement with the teeth of the energyabsorption strap to provide a locked condition.
 3. The locking mechanismof claim 2, wherein the lock cams are biased with a spring.
 4. Thelocking mechanism of claim 2, wherein rotation of the actuator bodyovercomes the bias of the lock cams to disengage the lock cams from theteeth of the energy absorption strap.
 5. The locking mechanism of claim4, wherein rotation of the actuator body directly rotates at least oneof the lock cams.
 6. The locking mechanism of claim 4, furthercomprising a lift linkage operatively coupled to the actuator body andat least one of the lock cams, the lift linkage overcoming the bias ofthe at least one lock cam.
 7. The locking mechanism of claim 1, whereinthe second direction is axially opposite the first direction.